Aug. 10 (Bloomberg) -- An explosion at a propane depot in North Toronto heard as far as 7 kilometers (4.4 miles) away has forced the evacuation of an area a mile around the site of the accident, the Canadian Broadcasting Corp. reported.

At least two people have been injured as the explosion blew out windows of homes nearby and sent plumes of smoke hundreds of meters into the air, the CBC reported, citing local police.

The explosion occurred at the Sunrise Propane depot near Keele and Wilson avenues shortly before 4 a.m. local time, the CBC reported. More than 100 firefighters called to the fire are focused on cooling two propane tankers to avoid further explosions, according to the CBC.

A 20-kilometer stretch of Highway 401, Canada's busiest highway, in north Toronto has been closed as a precaution, television news channel CP 24 reported, citing the Ontario Provincial Police.

Not pleasant, let me tell you. 12,000 people have been evacuated from the region and two major highways shut down. It's basically placed the city in gridlock, and some major flights have been cancelled.